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Discussion Starter · #1 ·
Hey guys on my 97 Polaris 680 Triple the middle exhaust pipe is not getting hot. Compression on all 3 pipes are the same being just over 100. I put a brand new spark plug in and checked and saw there a spark. I took out the carb and the bowl seemed to be full of gas. I was able to get the it running perfect earlier tonight after I reinstalled the carb. and then after I shut it off and restarted it the middle pipe would not get hot again. Maybe an electrical problem since it ran awesome for a little bit? Any suggestions?
 

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try swapping the carbs to see if bad cylinder follows carb ,, before you do the swap start it up, and make sure you have suction, [hand over back of carb] if you don't look at the reeds or a broken piston skirt ,, your compression. if reading correct is low, should be 130 , make sure you hold the throttle open when testing
 

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I would also swap plug wires from the center plug to either side to see if the problem follows the plug wire. If so, unscrew the plug boot and snip off about 1/4" of wire and screw the boot back on. Make sure the small screw inside the boot that makes contact with the wire is not corroded. If so, buy a new boot.
 

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Discussion Starter · #5 ·
So I rechecked the spark on all 3 plugs and the middle spark was very weak compared to the others. I tried cutting the wire and reinstalling the boot and it didn’t help. Also swapped boots and the middle plug was still weak. Do you think I should replace the ignition coil?
 

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Did you swap the middle wire to one of the outside cylinders? There is no firing order, all three plugs fire at the same time (three sparks per revolution). If you move the wire to an outside cylinder and that cylinder goes dead, it's electrical. Some coils will allow you to unscrew the wire on that end as well. Some are epoxied in, so that makes it a bit harder. I would check that before getting a different coil, as it's easy and free. I'm all about cheap repairs :D
 

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Discussion Starter · #7 ·
I replaced the coil and the middle cylinder fired right up! Took the sled for a rip and it ran so much better but still noticed bogging here and there and the other 2 pipes didn’t seem to get as hot as the middle one. Any ideas what I can do to fix that? Also I only drove 17 miles and my gas gage said I went from half to 1/4.
 
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